Beverages containing milk and fruit juice are well known and have long been considered desirable. It is known that the acid found in fruit juices can cause coagulation and curdling of milk when added to milk in amounts sufficient to lower milk's natural pH of 6.4-6.7 to below the isoelectric point (pH 4.6) of milk proteins. It is known that milk and juice blends can be made with previously acidified or soured milk. See, for example, U.S. Pat. No. 3,764,710. Unfortunately, beverages made in this manner tend to separate within a short time.
Food stabilizers including pectin, carboxymethylcellulose, xanthan gum, locust bean and combinations thereof have been used to prevent the coagulation and curdling of the milk and to provide stability to the beverages. See, for example, U.S. Pat. Nos. 2,818,342, 2,853,386 and 4,046,925, 4,078,092. Unfortunately, even when these food stabilizers are employed, beverage products containing milk and juice tend to exhibit undesirable sedimentation/precipitation over time.
A variety of means have been proposed to provide physical stability to beverage products which contain milk and juice. For example, U.S. Pat. Nos. 2,853,386 describes a beverage product which contains milk and juice and which is stable over time. However, the beverage product described therein requires prompt refrigeration after addition of the fruit juice so that the product will gel and prevent separation of ingredients. U.S. Pat. Nos. 4,061,792 describes the removal of tannins from juices before the addition to milk to reduce the curdling tendency of milk. U.S. Pat. Nos. 4,676,988 describes a cation/anion exchange process used to treat milk before adding acidic juices that minimizes curdling and/or precipitation. A number of other patents (for example, U.S. Pat. Nos. 3,625,702, 3,692,532, and 4,212,893) describe processes for preparing stable beverage products which contain milk and juice, but these processes require homogenization of the beverage which can be very expensive.
It would be desirable, therefore, to provide a stable beverage product which contains milk and juice, but which does not require homogenization or other special conditions (e.g., prompt refrigeration, removal of tannins from the juice or cation/anion exchange) to prevent separation of ingredients. The present invention relates to a process for preparing chilled or shelf stable beverage products which contain milk and a food acid (e.g. fruit juice), but which exhibit little or no sedimentation/precipitation over time and which are visually opaque. Moreover, the process of the present invention does not require homogenization in order to achieve these benefits.